Field of the Invention
The present invention relates to an object information obtaining system, a signal processing method, and a non-transitory storage medium.
Description of the Related Art
Object information obtaining systems such as photoacoustic imaging apparatuses or ultrasonic echo imaging apparatuses have been developed thus far as technologies for obtaining information inside an object, such as a living body, by detecting acoustic waves.
In the case, however, where the sound velocity of acoustic waves that propagate through media from an acoustic wave source to a probe is not constant, the acoustic waves are refracted. Detection signals of the refracted acoustic waves provide a low quantitativeness of object information. When the object information is converted into an image, the image consequently has distortion or a low contrast.
In order to minimize the above-described reduction of the quantitativeness of object information, the effect of the non-uniformity of the sound velocity has to be minimized. In the imaging technology using acoustic waves, the following method is included as an example of a method for reducing the effect of the non-uniformity of the sound velocity.
Japanese Patent Laid-Open No. 2010-167258 discloses a method for correcting the effect of refraction by tracing the propagation paths of acoustic waves in accordance with the Snell's law and calculating the arrival time from the propagation distance of the acoustic waves.
The method described in Japanese Patent Laid-Open No. 2010-167258 involves tracing of the propagation paths of multiple sound rays of acoustic waves, which have occurred as spherical waves, in accordance with the Snell's law and thus requires a large number of calculations. Consequently, the method described in Japanese Patent Laid-Open No. 2010-167258 is unsuitable for accelerating the calculations for correcting the effect of refraction.